It's a fair question! The TV does wonderful things for drama, but not engineering! Neither gearbox is particularly complex. The problem with RAPID in S9 was it was not designed it to be stripped and rebuilt in 2hours. We were tired, it wasn't worth the stess! The RAPID gearbox is spur gears, motors to wheels - it would be solid if we hadn't left some swarf in it!

Saturns or drills would be more than fine. But where's the fun in that!?